Navigation doesn't work when launching robot under a ns

edit

Hey, I'm trying to get multi-robot simulations on noetic. I used to do it in melodic using tf_namespace but now that it has been removed in noetic I cannot run them and the PR for restoring tf_prefix if failing checks. When I launch a robot with navigation in gazebo without a ns, it works fine.

The output from tf2_tools view_frames is -

The launch file is as follows -

<?xml version='1.0'?>
<launch>
    <!-- <group ns="dbot"> -->
        <arg name="x" default="0.0"/>
        <arg name="y" default="0.0"/>
        <arg name="z" default="0.0"/>    
        <param name="robot_description" command="$(find xacro)/xacro '$(find deliverybot_description)/urdf/dbot.xacro'"/>
        <node name="dbot_spawn" pkg="gazebo_ros" type="spawn_model" 
                output="screen" args="-urdf -param robot_description -model dbot -x $(arg x) -y $(arg y) -z $(arg z)">
        </node>        
        <node name="map_server" pkg="map_server" type="map_server" args="$(find deliverybot_navigation)/maps/willowgarage.yaml">
        </node>    
        <include file="$(find deliverybot_control)/launch/deliverybot_controller.launch">
        </include>
        <include file="$(find deliverybot_control)/launch/deliverybot_hw_controller.launch">
        </include>
        <include file="$(find deliverybot_navigation)/launch/move_base.launch">
        </include>
    <!-- </group> -->

</launch>

Now if I put this in a group under a namespace, this is warning I get -

[ WARN] [1614769555.770850662, 5.008000000]: Timed out waiting for transform from base_link to map to become available before running costmap, tf error: canTransform: target_frame map does not exist.. canTransform returned after 0.101 timeout was 0.1.

and frames -

There is no map frame and the links connected to differential drive controller plugin come under a different namespace than the rest of the links.

How should I proceed?